* {
    margin: 0;
    padding: 0;
}

body {
    background-color: #e0e0e0;
}

.container {
    width: 500px;
    height: 500px;
    margin: 100px auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
}

.main {
    width: 100%;
    height: 60%;
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    position: relative;
}

.progress {
    width: 100%;
    height: 5px;
    background: #fff;
    position: absolute;
    top: calc(50% - 2.5px);
    z-index: 1;
}

.progress span {
    width: 0%;
    height: 5px;
    background: #3498db;
    display: inline-block;
    position: absolute;
    transition: all 1s linear;
}

.container .circle {
    width: 50px;
    height: 50px;
    background-color: #fff;
    border: 3px solid #999;
    border-radius: 50%;
    color: #999;
    text-align: center;
    line-height: 50px;
    font-size: 20px;
    z-index: 1;
    transition: all 1s linear;
}

.btn {
    width: 100%;
    height: 50px;
    display: flex;
    justify-content: center;
}

.next:disabled {
    background: #999;
    cursor: not-allowed;
}

.prev:disabled {
    background: #999;
    cursor: not-allowed;
}

button {
    width: 100px;
    height: 40px;
    margin: 0 20px;
    background: #3498db;
    border: none;
    border-radius: 10px;
    color: white;
}

.active {
    border-color: #3498db !important;
}